Various activities require that a user or subject assume a first position, and then in response to an instruction, assume a second position. For example, security confirmation procedures may require a user to first face a camera, and then look away from a camera. Sports, exercise programs, training courses or physical therapy regimens may require a user or subject to assume one or more positions in the course of a session, and to then change such positions in response to for example one or more instructions. Currently, a trained observer instructs a user or subject to change a position, and then evaluates or corrects the subject's compliance with the instruction by observing the changed position.